KR940005539B1 - Process for producing receding of water agent of mortar and concrete - Google Patents

Abstract

The water reducing agent for mortar and concrete is prepared by adding formaldehyde to naphthol sulphonate produced from sulfating of naphthol, reacting at 60-90 deg.C for 10-20 hrs., separating the reacted compound from the not-yet reacted sulfuric acid deposits with salt, neutralizing the reacted compound to which the some content of basic material is added. The process of manufacture comprises the steps of sulfation, condensation, separation of insoluble component and neutralization. This water reducing agent has the advantages of good fluidity under lower water content, good workability, reduction of cracks and higher strength.

Description

Manufacturing method of mortar and concrete water reducing agent and water reducing agent

The present invention relates to a method for producing a mortar and concrete non-air-conducting water reducing agent mainly containing a condensate obtained by sulfating naphthol and condensing it with formalin or a neutralized product thereof, and a water reducing agent.

In general, high-performance water reducing agents have a strong cement dispersion effect, so adding them in the manufacture of concrete improves the fluidity of the concrete, making it easier to transport the concrete during construction and using less water. It is widely used in the manufacture of gypsum, mortar, concrete, etc. because of its quality improvement effect such as strength increase and crack reduction.

In particular, the fluidity of concrete facilitates the conveying work of concrete, which shortens the air and reduces the wear of the conveying equipment, resulting in a long service life and an energy saving effect during conveying. The invention is very important.

Conventionally, as such a water reducing agent, the condensate which condensed a naphthalene sulfonic acid homogeneous compound with formaldehyde (Japanese Patent Publication No. 61-83659), the formaldehyde condensate of sulfonated melamine, or the lignin sulfonic acid sodium salt is used.

The present invention is to provide an excellent water reducing agent having a higher fluidity of concrete than such a conventional water reducing agent.

The naphthol sulfonic acid was found to have a very high effect of dispersing cement particles in water because the naphthol sulfonic acid had a hydroxyl group (-OH) having a hydrogen bonding force between cement particles and water in addition to sodium sulfonic acid, which exhibits water-soluble dispersibility. It was found that when the high-condensation product condensed with formaldehyde was used as a water reducing agent, the fluidity of the cement was better.

The manufacturing method of the water reducing agent of the present invention is as follows.

Formaldehyde was added to naphtholsulfonic acid obtained by sulfated naphthol and reacted at 60 ° -90 ° C for 10-20 hours, and then calcium hydroxide or magnesium hydroxide was added to the reaction solution to precipitate unreacted sulfuric acid, thereby insoluble and insoluble. Preparation of the water sensitizer of the present invention is completed by controlling and neutralizing the reaction solution to pH 7-9 by appropriately introducing basic substances such as caustic soda into the reaction solution from which the powders (sediments) are separated.

An embodiment of the present invention will be described in detail by process.

EXAMPLE

[Step 1 (Sulfate Oxidation)]

After heating and dissolving 72 g of naphthol at 120 ° C., 57 g of 98% sulfuric acid at 120 ° C. was heated for about 2 hours, and the temperature was raised to 140 ° C., and then cooled to about 70 ° C. after the reaction for about 3 hours.

Second Process (Condensation Process)

Since naphthol (naphtholsulfonic acid) sulfated in the first step is generally high in viscosity, distilled water is added to an appropriate aqueous solution, and 56 g of formaldehyde (37% formalin aqueous solution) is added thereto and reacted at 80 ° C for 10-20 hours. The reaction is terminated when the reaction is 90% or more by analyzing in a conventional manner.

[3rd process (Insoluble matter separation and neutralization process)]

If the reaction solution obtained in the second step has a high viscosity, a small amount of water is added to the mixture, and the reaction is appropriately diluted. Then, 7.4 g of calcium hydroxide and 17 g of water are added to precipitate the unreacted sulfuric acid as a salt and the precipitated salt (insoluble content) is separated and removed. The reaction solution was obtained by neutralization (PH 7-9) by adding a caustic soda solution to the reaction solution, thereby completing the present invention.

You may use the liquid water reducing agent which neutralized the reaction liquid as it is, or spray-drying it as a powdery water reducing agent.

Powdered water reducing agents are easier to store and transport than liquid water reducing agents, or when used, they are liquefied into water and used again, so the effect is the same.

The water reducing agent of the present invention prepared as described above is generally used in a weight ratio of 0.01% -5% with respect to cement and tested by the following method, and the effect of the present water reducing agent is shown in Table 1 below.

Test method: Mixing and mixing the water reducing agent of the present invention and the conventional water reducing agent with a cement mortar at a predetermined ratio, put into a cylindrical flow measuring device (height 5cm, upper diameter 7cm, lower diameter 10cm) and lifted the mold after 1 minute The disc on which the cement mortar was placed was rotated 25 times for 15 seconds, and the diameter of the cement mortar which had flowed out at that time was measured in four directions, and the average value was taken as the slump value.

Compressive strength is a cement mortar was molded into a three-mould mold of the 4cm × 4cm × 16cm standard and cured in water for 28 days, and then tested according to JIS standard using a universal testing machine.

(The cement used in this test is Portland cement and sand is steel sand.)

TABLE 1

In Table (1), the conventional water reducing agent (1) is a condensation of naphthalene sulfonic acid homo-compound with formaldehyde.

Conventional water reducing agent (2) using the lignin sulfonic acid sodium salt as it is

Others do not use water reducing agents.

As can be seen from the above table (1), the slump of the cement mortar without the addition of the water reducing agent is 11.1 cm, whereas the conventional water reducing agent (1) using naphthalene sulfonic acid condensate salt has a synergistic effect of about 43.2%. On the other hand, the addition of the present invention was found to have a synergistic effect of about 61.3% as 17.9cm, and the conventional water reducing agent (1) was 389㎏ / ㎠ and the present invention was almost equivalent to 382㎏ / ㎠. It demonstrates strength and shows that the water reducing agent of this invention is excellent in fluidity | liquidity conventionally.

Therefore, the water reducing agent of the present invention is to improve the fluidity of the cement mortar more easily, the construction is more easy to shorten the various air, the service life of the equipment is long and the transfer energy is reduced.

Claims (2)

Preparation of mortar and concrete sensitizer prepared by adding formaldehyde to naphthol sulfonic acid sulfated naphthol and reacting at 60-90 ° C. for 10-20 hours, separating and removing unreacted sulfuric acid and neutralizing by adding a basic amount of basic substance. Way. A form reducing agent for mortar and concrete prepared by adding formaldehyde to naphthol sulfonic acid in which naphthol is sulfated and reacting at 60-90 ° C. for 10-20 hours, followed by sedimentation of unreacted sulfuric acid, and neutralization with an appropriate amount of basic substance.